1. Field of the Invention
The present invention relates to the field of image forming apparatuses. More particularly, it relates to the technical field of the ACS (Auto Color Selection) processing for determining whether or not a document is a color image.
2. Description of the Related Art
Conventionally, in color digital copying machines, there has been adopted a technology of using the ACS (Auto Color Selection) processing to automatically determine whether an image of each page read by an image reading section is a color image. According to this technology, color printing (first printing processing) is performed if it is determined that the image is a color image, or monochromatic printing (second printing processing) is performed if it is determined that the image is not a color image.
However, according to this kind of technology, for example, if a base of a document is colored like a colored paper and the like, the color of the base may cause the document to be determined as a colored document, so that the color of the base portion is reproduced in image forming. For example, if a character or drawing is depicted in black on a document having a chromatic base, and an area of the base portion is relatively large, a situation may arise where the base portion may cause color printing to be performed although a user thinks it is acceptable to perform monochromatic printing. If it is disadvantageous for a user, color toner is wasted.